According to US reports, it is understood that Chicago-based Leo Burnett has replaced Berlin Cameron and JWT without a competitive pitch and will now handle strategy and management of the global account.
A spokeswoman for WPP refused to comment about the reports, which are certain to deal a body blow to WPP chief executive Sir Martin Sorrell, who personally led the company's efforts to win the account during a long, drawn-out pitch process.
WPP was appointed last November following a review that began seven months previously. The deal, estimated to be worth around $700m (£394m), also involved other WPP agencies under the Group M banner handling media buying and Wunderman taking on direct marketing. However, media and direct activity are believed to be unaffected by the move.
At the time of WPP's appointment, it was reported that a substantial amount of local business, said to be worth a further $400m, was not included in the account. It was understood that local creative agencies and Publicis, which pitched for the main advertising account, would be considered for this work.
Work carried out by Berlin Cameron included a global campaign called "Imagine". Part of this features a TV spot where a man gets delivered a flat-screen TV meant for his neighbour by mistake.
The "Imagine" strapline has also be used in locally executed campaigns including the Vallance Carruthers Coleman Priest spot featuring the Chelsea FC manager Jose Mourinho. The manager is seen using his Samsung phone to photograph a young man playing football and then runs away over the tops of building to an office, where he prints this picture out, with the line "It's not that hard to imagine".
Samsung Mobile are the shirt sponsors for Chelsea, having taken over from Emirates this year.
This morning WPP was down 2p to 550p a fall of 0.36%.
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